Many vehicles have a warning light or other form of indication on the dashboard of the vehicle to show that a seat belt is not being used. Some vehicles are provided with a switch sensor inside a seat belt buckle which senses the position of a locking element in the buckle to determine whether or not the seat belt is in use. In such a vehicle, when the locking element is in a locking position holding a locking tongue of a seat belt, the warning light or indicator on the dashboard of the vehicle is switched off. When the locking element is disengaged from the locking tongue, the warning light or indicator is switched on.
Another known feature of seat belt buckles is to provide some form of lighting or illumination within or around the buckle to illuminate the buckle itself and specifically a slotted aperture of the buckle into which a seat belt locking tongue is to be inserted to make it easier to find the aperture so that the locking tongue of a seat belt can be readily inserted into and locked by the buckle.
A seat belt buckle incorporating both the switching means for a warning indicator on the dashboard and means to illuminate the buckle requires a large amount of wiring to be associated with the buckle and drawn through into the buckle.